1. Field of the Invention
The present invention relates to a method and apparatus for material metrology without contacting, destroying, or contaminating the material under test (MUT), using a high frequency probe. More specifically, the present invention relates to guided-wave GigaHertz (GHz) and Tera-Hertz (THz) spectroscopy for measuring material properties such as resistivity and dielectric response function (∈(xcfx89)).
2. Related Art
The conventional method in the semiconductor industry for measuring the sheet resistance of wafers and thin films is based on so-called xe2x80x9c4-point probe.xe2x80x9d The measurements involve direct contact of electrodes with the semiconductor wafer, rendering it useless for further processing. Thus, dummy wafers must be run through the various processing steps in order to calibrate the technological process.
It is a primary object of the present invention to provide a non-destructive probe for material metrology.
It is a further object of the present invention to provide a non-contact probe for material metrology.
It is a further object of the present invention to provide a non-contaminating probe for material metrology.
It is a further object of the present invention to provide method for measuring the resistivity of a material without destroying, without contacting, and without contaminating the material under testing (MUT).
It is another object of the present invention to provide probe for material metrology in the form of a waveguide which is placed adjacent to a MUT.
It is even an additional object of the present invention to provide a material metrology probe which operates into the Tera Hertz (THz) frequency range.
The present invention relates to a method and apparatus for material metrology (e.g., measurement of the complex conductivity of the material) as a function of a response to guided-wave GHz and THz signals. A high frequency wave is created and launched along a waveguide positioned in close proximity to an MUT. The wave is sampled initially, allowed to interact with the material, and sampled again. The samples are processed to derive information, such as resistivity or dielectric response function, of the material. The method and apparatus of the invention not only allows one to obtain information about the DC conductivity of metals, but also provides information about the high frequency behavior of materialsxe2x80x94both metals and dielectricsxe2x80x94which is becoming particularly useful at the time when processor clocks are running at frequencies exceeding GHz levels. The present invention provides for non-contact, non-destructive, and non-contaminating testing.